The invention is concerned with a toroidal angle detector for measuring angular displacement from the vertical, sometimes referred to as tilt. Toroidal sensors are known in the art. These commonly include a toroidal cavity enclosing an electrolytic liquid between different electrodes to form various conducting paths in the electrolyte. When the device tilts, only some portions of the electrodes are in contact with the electrolyte, so that the conductance of the different paths is a function of the angular displacement. The resistance or conductance of the various paths is then measured and compared to provide an indication of the tilt of the device.
In prior art devices it has been discovered that undesired leakage currents may degrade the precision of the transducer. Such leakage currents may be caused e.g. by external mechanical agitation which induces sloshing of the electrolyte onto the interior surfaces of the device above the liquid level. These leakage currents can degrade the precision of the measurement by slowing the response time to angular changes and by introducing instabilities which are time and temperature dependent.
It is therefore an object of the present invention to provide a toroidal angle detector which is insensitive to unwanted leakage currents.
In presently known toroidal detectors, the various conductance values required to provide an indication of the tilt of the device are measured separately e.g. by making a number of distinct voltage measurements. The separate voltages are then employed in an independent calculation to derive the angular measurement. In addition to the inherent complexities of this procedure, the necessity of making separate voltage measurements entails continuous electrical switching among various terminals which may introduce additional transducer leakage currents.
It is therefore another object of the present invention to provide a sensor in which the angular displacement may be simply determined from a single voltage measurement without extraneous calculation or switching of transducer terminals.